I'm having a simple blog system, with a posts, tags and posts_tags table. The posts and tags table both have an id and a content field, whereas the posts_tags table has the fields post_id and tag_id. My eloquent models are:
class Post extends \Illuminate\Database\Eloquent\Model
{
public function tags()
{
return $this->belongsToMany('Tag', 'posts_tags', 'post_id', 'tag_id');
}
}
and
class Tag extends \Illuminate\Database\Eloquent\Model
{
public function posts()
{
return $this->belongsToMany('Post', 'posts_tags', 'tag_id', 'post_id');
}
}
Now, as far as I understood, if I call Post::has('tags')->get() I should get the posts which have at least one tag (which all do). But all I get is an empty array (which I get when calling Tag::has('posts')->get(), too). What am I doing wrong?
Ok, found the problem in this question: Laravel Eloquent::Find() returning NULL with an existing ID
Problem was, I was using soft deletes
class Post extends \Illuminate\Database\Eloquent\Model
{
use SoftDeletingTrait;
protected $dates = ['deleted_at'];
public function tags()
{
return $this->belongsToMany('Tag', 'posts_tags', 'post_id', 'tag_id');
}
}
But my deleted_at column wasn't nullable.
Related
Example copied from official Laravel Docs:
For example, a Post model and Video model could share a polymorphic relation to a Tag model. Using a many-to-many polymorphic relation in this situation would allow your application to have a single table of unique tags that may be associated with posts or videos. First, let's examine the table structure required to build this relationship:
posts
id - integer
name - string
videos
id - integer
name - string
tags
id - integer
name - string
taggables
tag_id - integer
taggable_id - integer
taggable_type - string
From a tag object I wanted to get all the videos and posts, to which that subjected tag belongs (in case of morphOne an morphMany I can do that by morphTo() method)
Laravel says, I need to define both the videos and posts methods in Tag model in order to define an inverse but I want a relation like taggables which will return the respected parent (whether it's Post or Video)
Reference
I need a similar thing like imageable (but it is polymorphic one to one and I need this kind of thing in many to many)
You can just use MorphOne/MorphMany in your pivot model.
https://laravel.com/docs/8.x/eloquent-relationships#defining-custom-intermediate-table-models
class Video extends Model
{
public function tags()
{
return $this->morphToMany(Tag::class, 'taggable')->using(Taggable::class);
}
public function taggables()
{
return $this->morphMany(Taggable::class, 'taggable');
}
}
class Post extends Model
{
public function tags()
{
return $this->morphToMany(Tag::class, 'taggable')->using(Taggable::class);
}
public function taggables()
{
return $this->morphMany(Taggable::class, 'taggable');
}
}
class Tag extends Model
{
public function posts()
{
return $this->morphedByMany(Post::class, 'taggable')->using(Taggable::class);
}
public function videos()
{
return $this->morphedByMany(Video::class, 'taggable')->using(Taggable::class);
}
public function taggables()
{
return $this->hasMany(Taggable::class/*, 'tag_id'*/)
}
}
use Illuminate\Database\Eloquent\Relations\MorphPivot;
class Taggable extends MorphPivot
{
public $incrementing = false; // this is the default value. Change if you need to.
public $guarded = []; // this is the default value. Change if you need to.
protected $table = 'taggables';
public function taggable()
{
return $this->morphTo();
}
public function tag()
{
return $this->belongsTo(Tag::class/*, 'tag_id'*/);
}
}
I have two models Product and Images. I changed the route key name on the product model to use the slug field and i'm now unable to load the hasMany relationship with the Image Model
Here is the Product Model
class Product extends Model
{
protected array $with = ['images'];
public function getKeyName()
{
return 'slug';
}
protected array $guarded = [];
public function images() : HasMany
{
return $this->hasMany(Image::class, 'product_id');
}
}
and the Image model
class Image extends Model
{
protected array $guarded = [];
public function image() : BelongsTo
{
return $this->belongsTo(Product::class);
}
}
so when I try
Product::first()->images
it just returns an empty collection
but without overriding the getKeyName() method, everything works fine
getKeyName() will get the primary key for the model. it supports to return id, after you change it to slug, it will return slug
And hasManyHere's the source code ;
The third parameter LocalKey will use getKeyName() when it's empty.
If you still want to use hasMany, you need to pass the third parameter like this:
public function images()
{
return $this->hasMany(Image::class, 'product_id', 'id');
}
This will convert the Eloquent query to database query, which will take the right local key products.id.
Background: The application in question allows users to apply tags from a list of available tags. One article can have many tags and each tag may belong to many articles. The relationship between those is fine, but the complication comes in that a user should only see the tags which they have applied to the article. For instance, if Alice applies ['Apple', 'Banana', 'Cherry'] to article #1, Alice should not see Bob's article #1 tags of ['Grape', 'Orange', 'Kiwi'].
Ideal: An attach would work where the Auth'd user accesses the tags and applies it to an article by creating records in the intermediate pivot table. Additionally, if a user has applied a tag that does not exist yet, they should be able to insert new tags in the same action.
This action would be similar to how tags are applied to a StackOverflow post, actually.
The code I currently works, but just barely, so I wanted to see how others might organize the relationships between these. I'm also open to using a package if one exists that can handle this logic.
Relationships:
class User extends Authenticatable
{
public function articles()
{
return $this->hasMany('\App\Article');
}
public function articles_tags()
{
return $this->belongsToMany('\App\Article_Tag', 'article_tag_user', 'article_tag_id','user_id');
}
}
class Article extends Model
{
public function tags()
{
return $this->belongsToMany('\App\Tag', 'article_tag');
}
public function user()
{
return $this->belongsTo('\App\User', 'user_id');
}
public function article_tag_user()
{
return $this->hasManyThrough('\App\Tag', '\App\Article_Tag_User', 'article_id', 'id', 'article_id', 'tag_id');
}
}
class Tag extends Model
{
protected $fillable = [
'name'
];
public function user()
{
return $this->belongsToMany('\App\User', 'article_tag_user', 'id', 'article_tag_id');
}
public function articles()
{
return $this->belongsToMany('\App\Article', 'article_tag');
}
}
class Article_Tag extends Model
{
protected $table = 'article_tag';
public function user()
{
return $this->belongsToMany('\App\User', 'article_tag_user', 'user_id', 'article_tag_id');
}
public function tags()
{
return $this->belongsTo('\App\Tag');
}
}
class Article_Tag_User extends Model
{
protected $table = 'article_tag_user';
public function tags()
{
return $this->hasManyThrough('\App\Tag', '\App\Article_Tag');
}
}
Table Schema
Tag Table
|id|name|
Article_Tag Table
|id|article_id|tag_id|
Article_Tag_User
|id|user_id|article_tag_id|
You only need one pivot table (it also doesn't need an id):
article_tag_user: article_id | tag_id | user_id
Then you have BelongsToMany relationships between all combinations of Article, Tag, User.
I have three models:
Category
Post
Comment
These are their implementations:
class Category extends \Eloquent {
public function posts() {
return $this->hasMany('Post');
}
}
class Post extends \Eloquent {
public function category() {
return $this->belongsTo('Category');
}
public function comments() {
return $this->hasMany('Comment');
}
}
class Comment extends \Eloquent {
public function post() {
return $this->belongsTo('Post');
}
}
Is it possible, using eloquent, to get a list (array or collection) of all the comments (and only the comments, without posts) related to a Category?
(this means, given a category find all the related posts and then return all the related comments).
Thanks in advance!
Simply use hasManyThrough relation on your model Category :
class Category extends \Eloquent {
public function posts() {
return $this->hasMany(Post::class);
}
public function comments() {
return $this->hasManyThrough(Comment:class,Post::class);
}
}
After that, you can simply call $category->comments to have a Collection with all the comments related to a Category.
See https://laravel.com/docs/5.1/eloquent-relationships#has-many-through for extra information.
For Laravel 5.3 : https://laravel.com/docs/5.3/eloquent-relationships#has-many-through
Hello I'm trying to make script that show all categories and if category belongs to post this category should be checked with checkbox. My script wont works could you help me please. It shows only one checked category when have to shows two.
Controller Category model:
class Category extends Eloquent {
protected $table= "categories";
public function posts(){
return $this->belongsToMany('Post');
}
}
Post model
class Post extends Eloquent {
protected $table = 'posts';
public function categories(){
return $this->belongsToMany('Category');
}
}
catRelation:
[{"id":"45","post_id":"132","category_id":"1","created_at":"2014-12-26 20:32:41","updated_at":"2014-12-26 20:32:41"},{"id":"46","post_id":"132","category_id":"3","created_at":"2014-12-26 20:32:41","updated_at":"2014-12-26 20:32:41"}]
all categories: [{"id":"1","name":"Laravel","slug":"laravel","created_at":"-0001-11-30 00:00:00","updated_at":"-0001-11-30 00:00:00"},{"id":"3","name":"PHP","slug":"php","created_at":"-0001-11-30 00:00:00","updated_at":"-0001-11-30 00:00:00"}]
A category shouldn't ever belong to a post, but rather a post should belong to a category.
I assume catRelation is your pivot table. It's worth nothing that you need neither id, created_at or updated_at for this.
Example models:
class Post extends Eloquent
{
protected $table = 'posts';
public function category()
{
return $this->belongsToMany('Category', 'catRelation', 'category_id');
}
}
class Category extends Eloquent
{
protected $table = 'categories';
public function post()
{
return $this->belongsToMany('Post', 'catRelation', 'post_id');
}
}
Note: I may have got the final arguments in belongsToMany the wrong way around.